Why? is a book series edited by Simon Van Booy. He shares insights of Shakespeare, Blake, Sartre, and other luminaries on three perennial questions: Why We Need Love, Why Our Decisions Don't Matter and Why We Fight.
Each book has a cover design created around a question mark, symbolic for philosophy, combined with a visualisation of the concept. So basically, the cover tells the story of the book - and that's what book covers are for, right?
Unfortunately I haven't been able to find out who designed them, so if anyone knows, let me know (thx, Sonia!)